The present compound is represented by the following structural formula and shows an ORL-1 (opioid receptor-like 1) receptor agonistic activity (patent document 1). The present compound was produced in Example 18 of patent document 1.

Since a compound having an ORL-1 receptor agonistic activity is useful for the treatment of a mental disorder, and neuropathy and a physiological disorder, particularly for the improvement of anxiety and stress disorder, melancholia, traumatic disorder, loss of memory due to Alzheimer's disease or other dementia, symptoms of epilepsy and convulsion, acute and/or chronic pain symptom, remission of drug withdrawal symptoms including abstinence symptoms caused by cessation of abused drug, alcohol abuse, conttol of water balance, Na+ excretion, artery blood pressure disorder, eating disorders such as obesity and anorexia, and circadian rhythm sleep disorder (patent documents 1-10), the present compound is also useful for the prophylactic and/or treatment of the above-mentioned diseases.